According to auschwitz.org:
The second part was the Birkenau camp (which held over 90,000 prisoners in 1944), also known as "Auschwitz II" This was the largest part of the Auschwitz complex. The Nazis began building it in 1941 on the site of the village of Brzezinka, three kilometers from Oswiecim. The Polish civilian population was evicted and their houses confiscated and demolished. The greater part of the apparatus of mass extermination was built in Birkenau and the majority of the victims were murdered here.Various sub-camps were also built, but many of these have been demolished.
Birkenau was the largest of the more than 40 camps and sub-camps that made up the Auschwitz complex. During its three years of operation, it had a range of functions. When construction began in October 1941, it was supposed to be a camp for 125 thousand prisoners of war. It opened as a branch of Auschwitz in March 1942, and served at the same time as a center for the extermination of the Jews. In its final phase, from 1944, it also became a place where prisoners were concentrated before being transferred to labor in German industry in the depths of the Third Reich.
As the Soviet army approached and the end of the war came closer the vast majority of Auschwitz prisoners were marched west by the Nazis, into Germany. Those few thousand remaining were thought too ill to travel, and were left behind to be shot by the SS. In the confusion that followed the abandonment of the camp, the SS left them alive. The prisoners were found by Soviet forces when they liberated Auschwitz on January 27, 1945.
Vasily Gromadsky, a Russian officer with the 60th Army liberating Auschwitz recalls what happened.
"They [the prisoners] began rushing towards us, in a big crowd. They were weeping, embracing us and kissing us. I felt a grievance on behalf of mankind that these fascists had made such a mockery of us. It roused me and all the soldiers to go and quickly destroy them and send them to hell."
Dear Readers, please remember that these horrors were created by the same urbane and sophisticated society that previously brought us Martin Luther, Goethe, Schiller, Beethoven, and Bach. The camps demonstrated depths of depravity previously unimagined in cultured and civilized Europe. But evil lives very close below the surface of most societies. Government-sponsored and societal-approved brutality is insidious because ordinary people begin to believe that atrocities imposed on others is "normal" or quite all right. Consider how we treated African-Americans as late as the 1960s in the American South. It was "OK" to lynch blacks. And most people cannot or will not fight against the prevailing norms in their society - they just want to fit in. Considering the despicable hate talk we heard during the 2016 election in USA, remember the lessons of Auschwitz when you hear calls to imprison or deport Muslims and Mexicans, or when the specter of anti-semitism rears its ugly head again.
The square photographs were taken on Kodak Tri-X film with a Rolleiflex 3.5E with Xenotar lens. I developed the film in HC110 developer at dilution B for 4:30 minutes. I scanned the negatives with a Minolta Scan Multi medium-format scanner (approx. 2000 vintage). Click any picture to enlarge it to 2,400 pixels wide.